So i've been having this thought for awhile and I think Perk just isn't that good. He'd be a great back up and would be a solid locker room guy with championship experience not to mention he's a tough guy (something every team needs) but to me having that isn't worth not being able to extend Serge or James.

Durant for 5 more years (including this year) at about 17 mil/year
Westbrook 5 more year 16 mil/year (signed 5 years 80 mil)
Collison 4 more @ 3 mil/year rounding up
Thabo 3 more @ 3.5 mil/year
Cook expires after next season (3 mil)
Aldrich & Jackson & Hayward make about a combined 5 mil/year
Maynor 1 more year maybe 2 @ about 3 mil/year

Add that up you get... 50 Mil/year NOT INCLUDING Harden/Ibaka or Perk

i say let Maynor walk after next year or after this one cut him Jackson is a capable back up and cheaper. Let Cook walk too. that cuts about 6 mil/year leaving you with a cap total of 44 million. Amnesty Perk.
Sign Harden 11 mil/year 4-5 years and Serge 9mil/year for 3-4 years
Now the cap figure is about 64 million/year NOT IMPOSSIBLE. But with Perk getting 9 million a year you simply cannot resign Harden and Ibaka.

I agree, but you really want to get something in return for Perkins, picks if possible.

I would see if the Rockets would want Perkins for their 3 players they're not picking up the options on. Thabeet, Flynn, and Terence Williams.

Thabeet could probably fill in nicely for Perkins. The Thunder could then sign Thabeet for less and resign all the players they need to resign and let go of Flynn and Twill.

Thabeet would fit in really well with the Thunder front court as he's pretty athletic and long. The Thunder don't really need Thabeet to produce anything offensively. Perkins isn't that good offensively either. Thabeet and Ibaka would wreak havoc inside the paint.... so many blocked shots.

Harden is likely going to be getting the max. I guarantee you Cleveland would offer him more than 11 million, I can bet that any team that could would still offer him more than 11 million. Also the thing that you forgot was that even though Perk may not count at the salary cap if he is amnestied he would still cost the life of his contract to the thunder meaning that although they are not going to have to pay luxury tax on him they still have to pay for him meaning that OKC would be somewhere around 71 million per year + the luxury tax. I'm not sure what the luxury tax is, I think it is 68 million right? So when OKC fills out the rest of their roster they would be right at the luxury tax, and their roster will be worse than it is now.

Letting Perkins go is a mistake, and it could cost the Thunder a championship in the future, or the shot at multiple titles. Letting Harden go is even worse as he is a good scorer, and defender. The only thing that can stop OKC from winning a title is their owners willingness to spend, or possibly lack there of. I don't know the exact specifics of his finances though.

Perks being abit underrated here don't you think? He's a solid centre in a league that lacks centres. Sure 20 years ago he would be a back up but these days he's going to be needed if OKC want a championship.

Whether or not they keep Harden is irrelevant. Perkins does not fit the team. He can be a starter, but he might not have much trade value. I don't know. Amnesty or trade.

Ibaka is a center. He gets KILLED by PF's who stretch him, and he's more of a rim protector. Offensively, he has no post game and doesn't do anything as far as the pick n' roll. Add that he plays on a running team. He's a center.

Thabo is unnecessary on this team. Unless he's cool to be a backup. They need someone else alongside Westbrook. Harden should start. If he's gonna cost too much, then you can use him in a trade. Or, maybe, Westbrook will be traded. I think their big 3 should be their big 3.